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Yu, Y.-T. N.

Publications and source records attributed to Yu, Y.-T. N..

4 recordsLinked to original sources
bioRxiv2026

Predator adaptation to single prey species yields positive specialization and multiple forms of diversification

Ecological specialization emerges when adaptation to a focal context increases fitness in that context relative to others. Experimental evolution has been widely used to study microbial specialization in abiotic environments but not predatory specialization. Here we demonstrate evolutionary specialization by a bacterial predator and characterize associated diversification of its predation profile. Populations of the bacterium Myxococcus xanthus evolving on single, non-evolving prey species diverged in predatory performance, showing increased performance on their home prey relative to their common ancestor, and relative to foreign prey not encountered during adaptation. Adaptation to the single-prey environments resulted in striking radiation of performance profiles across a diverse panel of foreign prey that was shaped interactively by selection, chance, and indirect effects, with home-prey identity modulating the degree of stochastic indirect diversification. Despite a great diversity of indirect evolutionary effects, correlated evolution was net-positive, yielding positive predatory specialization as the general outcome. Genomic evolution mirrored phenotypic evolution in that degrees of genomic parallelism differed as a function of home-prey identity. These findings show that adaptation to even simple biotic conditions can generate great ecological and behavioral diversity, linking direct selection, deterministic indirect effects of adaptation, stochasticity, and the origins of predator specialization and diversification.

evolutionary biology↗
bioRxiv2024

Deletion of an sRNA primes development in a multicellular bacterium

ABSTRACTSmall non-coding RNAs (sRNAs) are essential in regulating gene expression during many biological processes. The myxobacteria gene pxr encodes an sRNA known to block fruiting-body development, an aggregative multicellular process triggered by starvation. Deletion of pxr allows Myxococcus xanthus cells to develop in the presence of nutrients. However, potential Pxr binding targets and most genes regulated by Pxr remain unknown. Here, we found that the absence of pxr expression dramatically alters the temporal dynamics of development, thus suggesting an important new role of this sRNA in myxobacterial ecology. We transcriptionally profiled vegetative cells of M. xanthus strains possessing vs lacking pxr and found that over half of the genes impacted by pxr deletion during growth are linked to development, including known and potentially novel critical regulators. Many other genes are associated with general metabolic processes, which Pxr regulates positively. Our study discovers new phenotypic effects of Pxr regulation of likely ecological importance, identifies the suite of genes this sRNA controls during vegetative growth, reveals a previously unknown developmental regulator and provides new insights into the early molecular regulation of myxobacterial development.

molecular biology↗
bioRxiv2021

Allopatric divergence limits cheating range and alters genetic requirements for a cooperative trait

Social defectors may meet diverse cooperators. Genotype-by-genotype interactions may constrain the ranges of cooperators upon which particular defectors can cheat, limiting cheater spread. The bacterium Myxococcus xanthus undergoes cooperative multicellular development, but some developmental defectors cheat on cooperators during this process. In this study, interactions between a cheater disrupted at the signaling gene csgA and allopatrically diversified cooperators reveal a very small cheating range. Expectedly, the cheater failed to cheat on all natural-isolate cooperators owing to non-cheater-specific antagonisms. Surprisingly, lab-evolved cooperators that diverged from their cheating-susceptible ancestor by fewer than 20 mutations and without experiencing cheating had already exited the csgA mutants cheating range. Cooperators might also diversify in the potential for a mutation to reduce expression of cooperative trait or generate a cheating phenotype. A new csgA mutation constructed in several highly diverged cooperators generated diverse sporulation phenotypes, ranging from a complete defect to no defect, indicating that genetic backgrounds can limit the set of genomes in which a mutation creates a defector. Our results suggest that natural populations feature geographic mosaics of cooperators that have diversified in their susceptibility to particular cheaters and in the phenotypes generated by any given cooperation-gene mutation. Significance statementSelection on cooperators exploited by obligate cheaters can induce evolution of resistance to cheating. Here we show that cooperators can also rapidly evolve immunity to cheating simply as a byproduct of evolutionary divergence in environments in which cooperation and cheating at the focal trait do not occur because the trait is not expressed. We also find that differences in the genomic context in which a cooperation-gene mutation arises can profoundly alter its phenotypic effect and determine whether the mutation generates a social defect at all - a pre-requisite for obligate cheating. These findings suggest that general divergence of social populations under a broad range of environmental conditions can restrict both the set of mutations that might generate social defectors in the first place and the host range of such defectors once they arise.

evolutionary biology↗